Comparing the caries-preventive effect of two fissure sealing modalities in public health care:: a single application of glass ionomer and a routine resin-based sealant programme.: A randomized split-mouth clinical trial

Aim. The aim of this study was to compare the caries-preventive effect of two types of sealant modalities and to evaluate whether the caries-preventive effect is related to sealant retention. A hypothesis was tested in which a glass ionomer sealant, once applied to the occlusal surface, was able to protect the fissure from caries even if the sealant appeared lost at visual inspection. Design. A 3-year randomized split-mouth trial evaluating two sealant modalities was performed at a public health centre in Finland. A chemically curing glass ionomer cement (GIC) and light-curing resin-based (RB) sealant material were applied randomly to the permanent second molars. Sealant application as a routine treatment procedure was carried out to 599 children in the age group of 12-16 years. Caries rate of the sealed teeth and sealant retention with both materials were analysed by a modified McNemar's test. The effectiveness, rate difference, and relative risk with both sealant materials were measured. Results. The difference in caries rate between the two modalities was highly significant. When compared to the GIC sealant method, the effectiveness of RB sealant method was 74.1% and the rate difference 3.2% (95% CI 1.44%, 4.98%). The relative risk for RB-sealed surfaces vs. GIC-sealed surfaces of having detectable dentin caries was 0.26 (95% CI 0.12, 0.57). The retention rate of sealants was higher with RB than GIC (P < 0.001). The effectiveness of the retention rate for RB sealants was 94.8% and the rate difference 87.2% (95% CI 83.86%, 90.50%). The relative risk during the 3-year study period of having a defective or lost RB sealant was 0.052 (95% CI 0.036, 0.075) when compared to having a defective or lost GIC sealant. Conclusion. It is concluded that in preventing dentin caries a RB sealant programme including resealing when necessary was more effective than a single application of GIC. The original hypothesis was thus falsified.